Aqueous dispersion of single-walled carbon nanotubes using tetra-phenyl bimesitylene derivative via noncovalent modification and improved antimicrobial activity

Article abstract of DOI:10.1166/jnn.2019.16762

Tetra-arylbimesityl derivative containing carboxylic groups have successfully been utilized in dispersing single-walled carbon nanotubes (SWNTs) in aqueous solutions through sonication and centrifugation procedures. The dispersion process and the characte

Full text of DOI:10.1166/jnn.2019.16762

Article
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Nanoscience and Nanotechnology
Vol. 19, 7960–7966, 2019
Copyright © 2019 American Scientific Publishers
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Printed in the United States of America
Aqueous Dispersion of Single-Walled Carbon Nanotubes
Using Tetra-Phenyl Bimesitylene Derivative via
Noncovalent Modification and Improved
Antimicrobial Activity
Elena Laura Ursu1, Irina Rosca1, Lucian G. Bahrin1, Lilia Clima1, Dana Bejan1, Monica C. Sardaru1,
Narcisa Marangoci1, Vasile Lozan1ꢀ2, and Alexandru Rotaru1ꢀ∗
1“Petru Poni” Institute of Macromolecular Chemistry, Romanian Academy, 700487 Iasi, Romania
2Institute of Chemistry of MECR of the Republic of Moldova, MD2028 Chisinau, Republic of Moldova
Tetra-arylbimesityl derivative containing carboxylic groups have successfully been utilized in dis-
persing single-walled carbon nanotubes (SWNTs) in aqueous solutions through sonication and cen-
trifugation procedures. The dispersion process and the characterization of final stabilized SWNTs
were accomplished using analytical techniques, providing sufficient evidences on the preparation
of the dispersed SWNTs in water. All the prepared SWNT water dispersions were evaluated for
antimicrobial activity against three different reference strains namely Escherichia coli, Staphylo-
IP: 5.189.204.16 On: Mon, 30 Dec 2019 08:01:01
coccus aureus and Candida albicans, and have shown considerable selective activity against the
Copyright: American Scientific Publishers
Gram-positive strain Staphylococcus aureus.
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Keywords: Tetra-Arylbimesityl Derivatives, Carbon Nanotubes, Aqueous Dispersion,
Antimicrobial Activity.
1. INTRODUCTION
inter-tubular van der Waals interactions between individ-
ual CNTs [9], it is desirable to explore ways to exfoli-
ate, individualize, disperse, and stabilize CNTs in various
media [10–15]. To the best of our knowledge, there are no
reports on non-covalent stabilization of CNTs with tetra-
arylbimesityls in either polar or non-polar solvents. Impor-
tantly, tetra-arylbimesityl derivatives containing functional
groups which increase their water solubility may serve as
intermediates for the preparation of water soluble CNTs
in a similar manner to polycyclic aromatic amphiphiles
based on perylenes [16], pyrenes [17–23] etc., contain-
ing hydrophilic groups covalently attached to the aromatic
backbones. These structures are known to disperse and sta-
bilize CNTs in aqueous media through strong and specific
interactions with CNTs by hydrophobic, ꢀ–ꢀ stacking
and charge transfer forces. Since tetra-arylbimesityls with
hydrophilic functional groups do possess similar proper-
ties with the already reported CNTs stabilizing polycyclic
aromatic compounds, and due to the great interest in new
amphiphilic molecules for CNT stabilization, we decided
Since the first reports on the synthesis of tetra-
arylbimesityls by Moorthy and co-workers [1–4], these
molecules have found applications as building blocks or
solid linkers in the construction of 2D or 3D metal organic
frameworks [2, 5] or supramolecular self-assemblies [4, 6].
The very specific properties of tetra-arylbimesityls derive
from the structure of the bimesitylene core, consisting
of a twisted geometry, where central phenyl rings are
locked into perpendicular positions by the steric repulsion
between the ortho-bound methyl groups. The attachment
of different aryl substituents to the bimesitylene scaffold
led to the development of efficient charge-carrier and emis-
sive materials in organic light-emitting diodes [6–8]. The
observed particular self-assembly properties and exten-
sive aromatic conjugation also make tetra-arylbimesityls
interesting candidates for the exfoliation and stabilization
of carbon nanotubes (CNT). Since CNTs are typically
available in the form of bundles hold together by strong
∗Author to whom correspondence should be addressed.
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doi:10.1166/jnn.2019.16762

Ursu et al.
Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetra-Phenyl Bimesitylene
to investigate the possibility of using tetra-arylbimesityls
in the preparation of water soluble dispersed CNTs.
Herein, we report the adapted synthesis of tetra-
arylbimesityls containing carboxylic groups, protocols
for single-walled carbon nanotubes dispersion in water
and comparison of antibacterial and antifungal investi-
gations of tetra-arylbimesityls native solutions and dis-
persions containing different amounts of single-walled
carbon nanotubes (SWNTs). The structure and stability
of the dispersed SWNTs hybrids were investigated by
atomic force microscopy (AFM), transmission electron
microscope (TEM), dynamic light scattering (DLS) and
Raman spectroscopy. Furthermore, both native compound
and the SWNT hybrid were also tested, and their antimi-
crobial activity evaluated, against three different reference
strains namely Escherichia coli (E. coli), Staphylococcus
aureus (S. aureus) and Candida albicans (C. albicans). We
believe that the ability of tetra-arylbimesityl derivatives to
disperse SWNTs in water may significantly expand the
existing toolbox for fabricating CNT-based materials for a
variety of applications.
and acidified to a pH of about 1–2 using 37% hydrochlo-
ric acid. The white precipitate thus formed was suction-
filtered, washed thoroughly with water, acetone (5–10 mL)
1
and air-dried. Yield 0.65 g (90%). H NMR (400 MHz,
DMSO-d6): ꢁ 12.98 (bs, 4H), 8.05–7.99 (m, 8H), 7.39–
7.31 (m, 8H), 1.65 (s, 12H), 1.63 (s, 6H) ppm. 13C NMR
(100 MHz, DMSO-d6): ꢁ 167.6, 146.5, 139.6, 138.6,
132.3, 131.4, 130.5, 130.1, 129.8, 19.5, 18.6 ppm.
TBM-E: TBM-A (0.18 g, 0.25 mmol) was suspended
in methanol (4 mL). To this suspension, thionyl chlo-
ride (0.5 mL, 6.9 mmol) was carefully added under a
nitrogen atmosphere and the resulting mixture was heated
to 50 ꢁC for 8 hours. The solution thus formed was
cooled down, poured over crushed ice and extracted with
dichloromethane (3 × 10 mL). The organic phase was
dried over sodium sulfate and the solvent was removed
using a rotary evaporator. The resulting residue was
purified using flash chromatography, using a mixture of
dichloromethane/hexane as eluent, yielding 0.15 g (80%)
1
of white powder. H NMR (400 MHz, CDCl3ꢂ: ꢁ 8.15–
8.10 (m, 8H), 7.34–7.28 (m, 8H), 3.96 (s, 12H), 1.69 (s,
12H), 1.67 (s, 6H) ppm. 13C NMR (100 MHz, CDCl3ꢂ:
ꢁ 167.1, 147.2, 139.4, 138.6, 132.5, 131.5, 129.8, 129.6,
128.6, 52.1, 19.2, 18.3 ppm.
2. EXPERIMENTAL DETAILS
2.1. Materials
All commercially available reagents were purchased in
their highest purity grade and used without further purifi-
2.3. General Procedure for Dispersing SWNTs
Commercial SWNTs were suspended in distilled water
(10 mg/mL) and, after 15 min sonication, rapidly, dif-
®
IP: 5.189.204.16 On: Mon, 30 Dec 2019 08:01:01
cation. SWNT SG 76 single-wall carbon nanotubes were
Copyright: American Scientific Publishers
purchased from Sigma Aldrich (Munich, Germany). The
ferent volumes were mixed with TBM-A water solu-
tion (3 mg/mL, 100 ꢃL NH4OH) in 400 ꢃL/100 ꢃL;
425 ꢃL/75 ꢃL; 450 ꢃL/50 ꢃL; 475 ꢃL/25 ꢃL;
490 ꢃL/10 ꢃL TBM-A/SWNTs ratios. The obtained dis-
persions were again sonicated for 30 min, followed by
centrifugation (5000 rpm, 5 min). The supernatant disper-
sions with color varying from light yellow to dark brown
depending on the amount of SWNTs were subsequently
used for characterization and biological activity tests.
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SWNTs were obtained by catalytic chemical vapor depo-
sition (CVD) method (CoMoCAT™).
2.2. Experimental
2.2.1. Synthesis of TBM-A
(3,3ꢀ,5,5ꢀ-tetrakis(4-carboxyphenyl)-2,2ꢀ,4,4ꢀ,6,6ꢀ-
hexamethyl-1,1ꢀ-biphenyl) and TBM-E
(3,3ꢀ,5,5ꢀ-tetrakis(4-methoxycarbonylphenyl)-
2,2ꢀ,4,4ꢀ,6,6ꢀ-hexamethyl-1,1ꢀ-biphenyl)
TBM-A: To a solution of potassium carbonate (3.04 g,
22 mmol) in water (10 mL), ethanol (10 mL)
and 1,4-dioxane (20 mL) were added. Nitrogen was
then bubbled for 15 minutes into the resulting solu-
tion, after which 3,3ꢀ,5,5ꢀ-tetraiodobimesityl 1 (0.74 g,
1 mmol), 4-carboxyphenylboronic acid (0.9 g, 5.4 mmol)
and tetrakis(triphenylphosphine)palladium (0) (0.2 g,
0.17 mmol) were subsequently added. The mixture was
then refluxed for 48 hours under a nitrogen atmosphere,
after which the reaction mixture was filtered. To the fil-
trate, water (100 mL) was then added and the pH of
the resulting solution was adjusted to about 1–2 using
37% hydrochloric acid. The precipitate thus formed was
suction-filtered, washed thoroughly with water and once
more suspended in water (100 mL). The pH of the suspen-
sion was then adjusted to about 9–10 using 20% ammo-
nium hydroxide and the resulting mixture was then filtered
2.4. Characterization and Measurement
UV-vis spectra were obtained with a PerkinElmer Lambda
35 UV-vis spectrophotometer (wavelength range 200–
1000 nm). Transmission electron microscopy (TEM)
images were obtained using Hitachi HT7700 microscope
operating at 100 kV in High Resolution Mode. TEM sam-
ples (3 ꢃL) were deposited on 300 mesh carbon-coated
copper grids and dried overnight before examination. The
samples for atomic force microscope (AFM) analysis were
deposited on freshly cleaved mica and recorded in air in a
tapping mode using NTEGRA Spectra (NT-MDT, Russia)
instrument with 3.1–37.6 N/m force constant cantilever of
a silicon nitride cantilevers (NSC10, NT-MDT, Russia).
Raman spectra for SWNTs samples were recorded using
a Raman spectrometer (inVia, Renishaw) in the solution
phase. The zeta potentials of the samples were evaluated
using a Delsa Nano-Particle Analyzer (Beckman Coulter)
J. Nanosci. Nanotechnol. 19, 7960–7966, 2019
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Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetra-Phenyl Bimesitylene
Ursu et al.
that measures the electrophoretic mobility of the particles
and converts it into the ꢄ potential using the von Smolu-
chowski equation. The results were expressed as the aver-
age of at three independent measurements performed for
each sample.
plates (Merk) for purity checking. Fungi were refreshed
on Sabꢁouraud dextrose agar (Merk) and were grown at
36 1 C, pH = 7.
Microbial suspensions were prepared with these cultures
in sterile saline solution to obtain turbidity optically com-
parable to that of the 0.5 McFarland standards (yielding a
suspension containing approximately 1 × 108 CFU mL−1
for all microorganisms). These suspensions were seeded
in 96-well tissue culture plates and incubated for 24 h
2.5. Antimicrobial Activity
The antimicrobial activity of TBM-A was determined
by disk diffusion bioassays [24] against three dif-
ferent reference strains: Escherichia coli ATCC25922,
Staphylococcus aureus ATCC25923 and Candida albicans
ꢁ
at 37 C in RPMI medium for yeast and Mueller-Hinton
broth medium for the bacterial strains. The same media
were used to prepare serial dilutions of the compounds
to be tested. The SWNTs concentration range of the
tested compounds was 10, 25, 50, 75 and respectively
100 mg/mL. After 24 hours of incubation, the medium
was replaced with 100 ꢃL per well of the previously pre-
pared dilutions and the plates were further incubated for
20 h. The CellTiter 96sAQueousOne Solution reagent was
then added to each well and, after final 4 h incubation
the absorbance at 490 nm was recorded with an EnVisions
plate reader (PerkinElmer).
ꢁ
ATCC10231. All microorganisms were stored at −80 C
in 20% glycerol. The bacterial strains were refreshed in
ꢁ
Mueller-Hinton broth at 36 C, and the yeast strain was
ꢁ
refreshed on Sabouraud dextrose agar at 36 C. Microbial
suspensions were prepared with these cultures in sterile
solutions to obtain turbidity optically comparable to that
of 0.5 McFarland standards (yielding a suspension con-
taining 1 × 108 CFU mL−1 for all the microorganisms).
Volumes of 0.5 mL from each inoculum were spread onto
Mueller-Hinton agar and the compound was added after
drying of the medium surface. The stock solutions were
prepared using DMSO as a solvent. The active principle
concentration range of the tested compound (TBM-A) was
between 0.005 and 3 mg/mL. First, an aliquot (50 ꢃl) was
added on sterilized paper discs (6 mm) and afterwards
was incubated in the plates with the microorganisms. To
evaluate the antimicrobial properties, the growth inhibi-
tion was measured after 24 hours of incubation at 36
3. RESULTS AND DISCUSSION
3.1. Synthesis and Characterization
Following the reported procedure [4], we have adapted
the synthetic pathways for the preparation of two tetra-
arylbimesityl derivatives (Scheme 1) to be tested as
IP: 5.189.204.16 On: Mon, 30 Dec 2019 08:01:01
Copyright: American Scientific Publishers
SWNTs stabilizers. The compounds, labeled as TBM-A
(acid) and TBM-E (ester), were tested for water solubil-
ity resulting in the fact that only TBM-A showed water
solubility in the presence of 10 equivalents of ammo-
nia to yield a clear water solution. Compound TBM-E
did not show any significant water solubility and was not
used in further investigations. In order to explore the abil-
ity of TBM-A to water disperse SWNTs and the corre-
lation between the amount of TBM-A, dispersing time
and dispersing efficiency, a water/ammonia stock solu-
tion (3 mg/mL) was prepared. Separately, SWNT were
suspended in water (10 mg/mL) and used as SWNT
stock dispersions in further experiments. Typically, in a
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ꢁ
1 C. All tests were carried out in triplicate to verify the
results. After incubation, the diameters of the inhibition
zones were evaluated.
To assess the cytotoxicity of TBM-A/SWNTs disper-
sions, the CellTiter 96sAQueous One Solution Cell Pro-
liferation Assay (Promega) was performed on Candida
albicans ATCC10231, Escherichia coli ATCC 25922 and
Staphylococcus aureus ATCC25923, by following the pro-
tocol recommended by the manufacturer. All microorgan-
isms were stored at −80 ꢁC in 10% glycerol. The bacteria
were refreshed in Mueller–Hinton broth (Merck) at 36
ꢁ
1 C, and afterward were inoculated on Plate Count Agar
HOOC
COOH MeOOC
COOMe
I
I
I
I
I
II
90%
80%
1
TBM-A
TBM-E
HOOC
COOH MeOOC
COOMe
Scheme 1. Synthesis of tetra-arylbimesityl derivatives TBM-A and TBM-E; I) 4-carboxyphenylboronic acid, K2CO3, Pd(PPh3)4, ethanol, water,
1,4-dioxane; II) SOCl2, methanol.
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Ursu et al.
Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetra-Phenyl Bimesitylene
Raman spectroscopy is suitable technique to
fixed volume (500 ꢃL) different ratios of TBM-A and
SWNTs stock dispersions were tested. Five ratios of TBM-
A/SWNTs dispersions (400 ꢃL/100 ꢃL; 425 ꢃL/75 ꢃL;
450 ꢃL/50 ꢃL; 475 ꢃL/25 ꢃL; 490 ꢃL/10 ꢃL) were pre-
pared under 30 min sonication, followed by centrifugation
at 5000 rpm for 5 min. The obtained brown to dark-
brown supernatants were then separated and characterized.
All dispersions have shown structured absorption spectrum
(Fig. 1(A)) in the range of 550–900 nm characteristic to
the dispersed SWNTs in aqueous solution [25–27].
a
investigate and characterize dispersed SWNTs and SWNT
bundles [28]. The Raman spectra of TBM-A/SWNT
dispersions (ꢅex = 633 nm) at various concentrations
are shown in Figures 1(B), (C). The D-band and the
G-band were observed at 1343 and 1591 cm−1 respec-
tively, corresponding to the sp3 and sp2 hybridized car-
bon atoms in the SWNTs [29]. The intensity of the
G-band reflects the content of individual SWNT, while
the D-band value corresponds to the existing impurities,
for example, aggregates [20]. For the examined disper-
sions of TBM-A/SWNTs, the D-band/G-band intensity
ratio decreased from 0.4 to 0.2 after the sonication exfoli-
ation with TBM (Fig. 1(B)). The observed decrease of the
D-band/G-band intensity ratio and the increased intensity
of radial breathing mode region (170–280 cm−1) in Raman
spectra demonstrated that the SWNT bundles were effec-
tively exfoliated by TBM-A molecules [20, 30]. Besides
the increasing of the G-band intensity with the increase of
the amount of SWNTs in the sample, we have also inves-
tigated the G-band values variation with the sonication
time (Fig. 1(C)). The starting TBM-A/SWNT dispersion
(400 ꢃL/100 ꢃL ratio of stock solutions) was sonicated
for 30 min, while Raman spectra of the mixture were
measured at 0, 15 and 30 min. The increase of G-band
intensity with the sonication time by 25% was clearly
observed. Subsequent sonication of the dispersion did not
result in the further increase of the G-band intensity under
IP: 5.189.204.16 On: Mon, 30 Dec 2019 08:01:01
Copyright: American Scientific Publishers
the investigated conditions.
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The observed dispersion of SWNTs by TBM-A detected
by Raman spectroscopy was further investigated and con-
firmed using TEM and AFM techniques. Figures 2(A), (B)
presents the TEM images of TBM-A/SWNT dispersion
(400 ꢃL/100 ꢃL ratio of stock solutions) before and after
30 minute sonication process. Thus, TEM images prior
to sonication revealed that the TBM-A/SWNT dispersions
existed as aggregated bundles and dense network structures
(Fig. 2(A)). Upon sonication with the TBM-A aqueous
solution, SWNTs were still locally observed as bundles,
but with the clear presence of multiple isolated tubes with
the length in the range 200–600 nm (Fig. 2(B)). The AFM
characterization further provided evidences of SWNT dis-
persion under similar conditions (Fig. 2(C)), revealing the
elongated SWNTs together with multiple short fragments
on the mica surface. The accurate evaluation and measure-
ments of the height profiles of the dispersed SWNTs by
AFM was impeded by the excess of TBM-A in the sample,
providing multiple bulky crystalline agglomerations on the
analyzed surface appearing as bright spots in the image.
The mica surface washing with distilled water led to the
complete removal of both crystals and the SWNTs from
the surface (data not shown). Still, in the analyzed images
we could not observe SWNTs large aggregated bundles or
dense networks.
Figure 1. (A) UV-Vis spectra of different ratios between TBM-
A/SWNTs in water; (B) Raman spectra for SWNTs in various concen-
trations. (C) Raman spectra for SWNTs at various sonication time.
Finally, ꢄ potential as a function of the amount of
SWNTs in water dispersion was measured and the results
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Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetra-Phenyl Bimesitylene
Ursu et al.
Figure 3.
ꢄ potential values for the TBM-A/SWNT dispersions
(400 ꢃL/100 ꢃL; 425 ꢃL/75 ꢃL; 450 ꢃL/50 ꢃL; 475 ꢃL/25 ꢃL;
490 ꢃL/10 ꢃL).
ꢄ potential value determined (−80 mV) for the strongest
SWNT composite film prepared by the treatment of
SWNTs with nitric acid [31, 32].
3.2. Antimicrobial Activity
First, the antimicrobial activity screening of compound
TBM-A alone was evaluated. It was measured by the agar
disk diffusion method [24] which supposes the addition
of the TBM-A compound on the culture medium pre-
inoculated with the microbial suspension, and measuring
of the clear zone caused by the growth inhibition around
IP: 5.189.204.16 On: Mon, 30 Dec 2019 08:01:01
the film disks after 24 h of incubation. All the tested
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concentrations (between 0.04 and 24 mg/mL) showed no
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antimicrobial activity against the reference strains repre-
sented by E. coli and C. albicans but the compound proved
to be efficient against S. aureus, at a minimum inhibitory
concentration of 3 mg/mL. The data on the diameters of
the inhibition zones are presented in Table I.
Next,
all
the
TBM-A/SWNT
dispersions
Figure 2. TEM images of the TBM-A/SWNT dispersion
(400 ꢃL/100 ꢃL) before (A) and after (B) sonication; (C) AFM images
of the TBM-A/SWNT dispersion (400 ꢃL/100 ꢃL) after sonication.
(400 ꢃL/100 ꢃL; 425 ꢃL/75 ꢃL; 450 ꢃL/50 ꢃL;
475 ꢃL/25 ꢃL; 490 ꢃL/10 ꢃL) were evaluated against
three different reference strains namely Escherichia coli
(E. coli), Staphylococcus aureus (S. aureus) and Candida
albicans (C. albicans) (Fig. 4). Analyzing the obtained
results we have observed that none of the investigated dis-
persions presented antimicrobial activity against the yeast
strain C. albicans and against the Gram-negative strain
E. coli (Fig. 4). Contrarily, all the tested SWNTs disper-
sions presented selective antibacterial activity against the
Gram-positive strain S. aureus, the viability of the cells
are presented in Figure 3. For the analyzed dispersed
TBM-A/SWNTs dispersions, the absolute value of the
ꢄ potential varied in the range between −25 and −45 mV
depending on the amount of SWNTs in dispersion. Thus,
the highest value (−26 mV) of the ꢄ potential was
obtained for the TBM-A/SWNT dispersion containing the
smallest amount of SWNTs (490 ꢃL/10 ꢃL ratio of stock
solutions). Vice versa, the lowest value (−46 mV) was
determined in the case of TBM-A/SWNT dispersion con-
taining the highest amount of SWNTs (400 ꢃL/100 ꢃL
ratio of stock solutions). This indicates that all the ana-
lyzed dispersions are fairly stable [31] in water and the
stability of the dispersions is largely determined by the
electrostatic repulsion due to the surface charge ensured
by the carboxylic groups of TBM-A molecules from the
SWNTs template. These data go along with the reported
Table I. Antibacterial activity of TBM-A against the reference strains
(cm).
Inhibition zone (cm)/TBM-A concentration (mg/mL)
Strain
24
12
6
3
1.5 0.75 0.375 0.187 0.093 0.04
S. aureus
E. coli
C. albicans
1.305 1.054 0.793 0.676
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
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Ursu et al.
Aqueous Dispersion of Single-Walled Carbon Nanotubes Using Tetra-Phenyl Bimesitylene
120
E. coli. Besides the interesting selective biological activity
of the new stabilized SWNTs, the current research pro-
vides an important synthetic protocol for the preparation
of –COOH-functionalized SWNTs that may lead to the
design of novel 3D carbon-based systems for application
in sensing, drug delivery or construction of SWNT-based
Metal Organic Frameworks.
100
80
60
40
20
0
Acknowledgments: The financial support of European
Social Fund for Regional Development, Competitiveness
Operational Programme Axis 1 – Project “Novel Porous
Coordination Polymers with Organic Ligands of Variable
Length for Gas Storage,” POCPOLIG (ID P_37_707, Con-
C
TBM-A
10
25
50
75
100
tract 67/08.09.2016, cod MySMIS: 104810) is gratefully
acknowledged.
C.albicans
S.aureus
E.coli
Figure 4. Cytotoxicity of the
TBM-A/SWNT
dispersions
(400 ꢃL/100 ꢃL; 425 ꢃL/75 ꢃL; 450 ꢃL/50 ꢃL; 475 ꢃL/25 ꢃL;
490 ꢃL/10 ꢃL) against all the investigated reference strains.
References and Notes
1. Moorthy, J.N., Venkatakrishnan, P., Natarajan, P., Huang, D.-F. and
Chow, T.J., 2008. De novo design for functional amorphous mate-
rials: Synthesis and thermal and light-emitting properties of twisted
anthracene-functionalized bimesitylenes. Journal of the American
Chemical Society, 130(51), pp.17320–17333.
ranging between 70.91% for compound TBM-A alone and
41.46% for TBM-A/SWNT (400 ꢃL/100 ꢃL), depending
strongly on the amount of SWNTs in dispersion (Fig. 4).
These results partially come along with the literature
reports regarding dispersed SWNTs having antimicrobial
properties against several types of bacterial and yeast
strains and preventing pathogens adhesion and biofilm for-
mation [33–35]. On the other hand, Kang et al., [36]
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J.N., 2005. Corundum, diamond, and PtS metal–organic frame-
works with
a difference: Self-assembly of a unique pair of
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Copyright: American Scientific Publishers
[37] of CNTs determines their antibacterial activity against
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cell-surface interaction. These data clearly show the impor-
tance of the SWNTs surface nature upon their selective
antibacterial or antifungal activity. Thus, SWNTs with
surface groups –OH and –COOH are known to exhibit
extremely strong antimicrobial activity against both Gram-
positive and Gram-negative bacteria, proving that nano-
tubes destroy bacteria regardless of the wall structure or
cell shape [38]. This could be also observed in our case,
the –COOH groups of the dispersed SWNTs provided
by TBM-A molecules have also shown selective activity
against Gram-positive S. aureus.
5. Yan, Y., O’Connor, A.E., Kanthasamy, G., Atkinson, G., Allan, D.R.,
Blake, A.J. and Schröder, M., 2018. Unusual and tunable negative
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In summary, we have succeeded in dispersing SWNTs
using for the first time a tetra-arylbimesityl deriva-
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aqueous dispersion through sonication and centrifuga-
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Received: 16 November 2018. Accepted: 6 December 2018.
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